Chronic prostatitis/chronic pelvic pain syndrome (collectively referred to herein as CPPS) is a syndrome of undetermined etiology occurring in men. CPPS is the third of four subgroups of prostatitis recognized by the National Institutes of Health. Category I encompasses acute bacterial prostatitis, and Category II covers chronic bacterial infection. Category III, CPPS, includes all remaining prostatitis syndromes, and is subdivided into IIIa (inflammatory) and IIIb (non-inflammatory). These sub-categories can be distinguished by the presence of leukocytosis in expressed prostatic secretions or sediment in a post-massage urine sample. Category IV represents asymptomatic prostatitis, which often is associated with benign prostate hyperplasia.
Prostatitis is extraordinarily common, resulting in approximately 2 million office visits to primary care physicians and urologists in the United States annually (1997 American Urological Association Annual Meeting, National Ambulatory Medical Care Survey, National Center for Health Statistics, 1990 to 1994). Patients with CPPS suffer from chronic, episodic pain in the perineum or pelvic region, irritative and obstructive voiding symptoms, and adverse effects upon sexual function (Alexander et al., Urology 48:568-574 (1996)). Men with chronic prostatitis often require repeated physician visits. Medical expenditures relating to CPPD are conservatively estimated to exceed half a billion dollars annually.
While an enormous number of patients seek the care of a physician because of prostatitis-like symptoms, almost nothing is known about diagnostic criteria, etiology, or objective signs for CPPS. Pain in the pelvic region is the most frequently reported and the most severe symptom in patients with CPPS (Alexander et al., Urology 48:568-74 (1996)). It was because of these observations and the paucity of objective criteria for defining the disease, which the National Institute of Diabetes and Digestive and Kidney Diseases working group in prostatitis suggested that the disease be named Chronic Pelvic Pain Syndrome.
One reason for the present state of confusion regarding CPPS is the similarity of CPPS symptoms to the symptoms of bacterial prostatitis. Only about 5 to 10% of patients whose symptoms are consistent with bacterial prostatitis are shown to have infection in the prostate gland (Weidner et al., Infection 19:S109-S190 (1991)). The misdiagnosis of CPPS as infectious prostatitis commonly results in unnecessary treatment with multiple courses of antibiotics at burdensome costs to patients and to the health care system with no demonstrated benefit to patients.
Much effort has been expended to identify an organism underlying the cause of CPPS but no clear consensus has emerged identifying any such organism as the causative agent. Additionally, some men with CPPS have evidence of inflammation of the prostate. While the cellular and cytokine mediators involved in the inflammatory process have been increasingly clarified in the immunologic literature, few studies have investigated the immunobiology of the prostate gland to determine whether CPPS might arise from an auto-immune-like condition.